Document U.S. Pat. No. 8,740,140, also published as US2014263832 and FR 2 939 099, is incorporated by reference. This document discloses a device comprising at least:                a first shaft rotatably mounted on the aircraft to rotate about an axis of rotation that is substantially parallel to a hinge axis hinging the undercarriage to the aircraft;        a telescopic second shaft rotatably mounted on the undercarriage and extending down along the undercarriage to the proximity of wheels carried thereby;        transmission means for transmitting rotary motion from the first shaft to the second shaft;        transmission means for transmitting rotary motion from the second shaft to at least one wheel carried by the undercarriage;        if the wheel is not fitted with a brake, means for selectively braking one of the shafts relative to the undercarriage; and        motor means adapted to cause the first shaft to rotate.        
That type of device makes it possible not only to drive the wheels in rotation, but also to extend and to raise the undercarriage. In the embodiment shown in that document, the undercarriage is fitted with two telescopic second shafts extending on either side of the undercarriage, each co-operating with a respective one of the wheels.
The second shafts extend down of the sides of the undercarriage so they are exposed to external attacks, in particular to impacts from stones and to carbon dust projected from brake disks, which attacks run the risk of having an influence on the lifetime of the device.